Crystal structures and vibrational and solution and solid-state (CPMAS) NMR spectroscopic studies in triphenyl phosphine,arsine, and stibine silver(I) bromate systems, (R3E)xAgBrO3 (E = P,As, Sb; x = 1-4)

Adducts of triphenyl phosphine, triphenyl arsine, and triphenyl stibine with silver(I) bromate have been synthesized and characterized both in solution ((1)H and ESI MS spectroscopy) and in the solid state (IR, single-crystal X-ray structure analysis). The triphenyl phosphine complexes have been also investigated by (31)P[(1)H] solution and (31)P cross-polarization magic-angle-spinning (CPMAS) NMR spectroscopy. The topology of the structures in the solid state was found to depend on the nature of EPh(3) and on the stoichiometric ratio AgBrO(3)/EPh(3). In AgBrO(3)/PPh(3) (1:1)(4) (1) and AgBrO(3)/PPh(3) (1:2) (2), the bromate is in the unfamiliar and hitherto structurally uncharacterized role of coordinating ligand, the complex having a mononuclear form in 2 and a less familiar tetrameric form in 1. In AgBrO(3)/AsPh(3) (1:4).CH(3)OH (7) and AgBrO(3)/SbPh(3) (1:4).C(2)H(5)OH (11), the cations are the familiar homoleptic [Ag(EPh(3))(4)](+) array with the bromate role simply that of counterion. The AgBrO(3)/AsPh(3) (1:2)(2).0.7"H(2)O" derivative (6) is binuclear L(2)Ag(mu-BrO(3))(2)AgL(2) with a four-membered ring core (L = AsPh(3)).     

Method validation for determination of alkaloid content in goldenseal root powder

A fast, practical ambient extraction methodology followed by isocratic liquid chromatography (LC) analysis with UV detection was validated for the determination of berberine, hydrastine, and canadine in goldenseal (Hydrastis canadensis L.) root powder. The method was also validated for palmatine, a major alkaloid present in the possible bioadulterants Coptis, Oregon grape root, and barberry bark. Alkaloid standard solutions were linear over the evaluated concentration ranges. The analytical method was linear for alkaloid extraction using 0.3-2 g goldenseal root powder/100 mL extraction solvent. Precision of the method was demonstrated using 10 replicate extractions of 0.5 g goldenseal root powder, with percent relative standard deviation for all 4 alkaloids < or = 1.6. Alkaloid recovery was determined by spiking each alkaloid into triplicate aliquots of neat goldenseal root powder. Recoveries ranged from 92.3% for palmatine to 101.9% for hydrastine. Ruggedness of the method was evaluated by performing multiple analyses of goldenseal root powder from 3 suppliers over a 2-year period. The method was also used to analyze Coptis root, Oregon grape root, barberry bark, and celandine herb, which are possible goldenseal bioadulterants. The resulting chromatographic profiles of the bioadulterants were significantly different from that of goldenseal. The method was directly transferred to LC with mass spectrometry, which was used to confirm the presence of goldenseal alkaloids tetrahydroberberastine, berberastine, canadaline, berberine, hydrastine, and canadine, as well as alkaloids from the bioadulterants, including palmatine, jatrorrhizine, and coptisine.     

Ultrafast intensity modulation by Raman gain for all-optical in-fiber processing

We present experimental results on ultrafast intensity modulation using the Raman effect and demonstrate 10-Gbit/s selective pulse erasure. The technique is both broadband and polarization insensitive and has a potential speed in excess of 500 Gbits/s. In addition to performing pulse erasure, this all-optical modulator can shape pulses as a precise, soft aperture scalpel and create short, dark pulses.     

A new proof of Federer's structure theorem for

We prove that Federer's structure theorem for -dimensional sets in follows from the special case of -dimensional sets in the plane, which was proved earlier by Besicovitch.

     

Analysis of cesium extracting solvent using GCMS and HPLC

A high-level waste (HLW) remediation process scheduled to begin in 2007 at the Savannah River Site is the Modular Caustic Side Solvent Extraction (CSSX) Unit (MCU). The MCU will use a hydrocarbon solvent (diluent) containing a cesium extractant, a calix[4]arene compound, to extract radioactive cesium from caustic HLW. The resulting decontaminated HLW waste or raffinate will be processed into grout at the Saltstone Production Facility (SPF). The cesium containing CSSX stream will undergo washing with dilute nitric acid followed by stripping of the cesium nitrate into a very dilute nitric acid or the strip effluent stream and the CSSX solvent will be recycled. The Defense Waste Processing Facility (DWPF) will receive the strip effluent stream and immobilize the cesium into borosilicate glass. Excess CSSX solvent carryover from the MCU creates a potential flammability problem during DWPF processing. Bench-scale DWPF process testing was performed with simulated waste to determine the fate of the CSSX solvent components. A simple high performance liquid chromatography (HPLC) method was developed to identify the modifier (which is used to increase Cs extraction and extractant solubility) and extractant within the DWPF process. The diluent and triocytlamine (which is used to suppress impurity effect and ion-pair disassociation) were determined using gas chromatography mass spectroscopy (GCMS). To close the organic balance, two types of sample preparation methods were needed. One involved extracting aqueous samples with methylene chloride or hexane, and the second was capturing the off gas of the DWPF process using carbon tubes and rinsing the tubes with carbon disulfide for analysis. This paper addresses the development of the analytical methods and the bench-scale simulated waste study results.